Following your thread drift, I'm involved with a Mission Computer System for a particular airborne application, which is mission critical (though not flight critical).
Guess which operating system it'll use?
Yes - MS Windows XP!
Agree with you about the handling fidelity of simulators. The ones I used to instruct on as part of my RAF job did not replicate the stick force gradient of the real a/c properly and were less stable at certain speeds. They were far more difficult to fly on 2 engines - a full power double asymmetric go-around was an utter doddle by comparison in the real a/c as we allowed students to experience for themselves during training. But the beancounters wanted increasingly less experienced pilots to do more of their training in the wretched sweat boxes.....